The invention relates to a gas turbine combustion chamber.
In particular, the invention relates to a gas turbine combustion chamber with an inner combustion chamber wall and an outer combustion chamber wall, which form an annular combustor. Mixing air holes through which admixing air is guided into the interior space of the combustion chamber are formed in a circumferentially distributed manner in the inner combustion chamber wall and in the outer combustion chamber wall.
In particular, the invention relates to a gas turbine combustion chamber as it is described in WO 2014/149081 A1. Such a combustion chamber works according to the “counter swirl doublet mixer concept”. The combustion chamber, which can be constructed in a modular design with individual modules that arranged around the circumference and connected to each other, comprises an outer and an inner combustion chamber wall, as well as a head plate inside of which recesses, through which fuel nozzles can reach the combustion space, are provided. The combustion chamber itself is embodied with one wall, so that the outer combustion chamber wall and the inner combustion chamber wall are manufactured from formed sheet metal, for example. Mixing air holes, through which admixing air is supplied, are provided in a circumferentially distributed manner. At that, respectively two mixing air holes are positioned in pairs directly next to each other according to the “counter swirl doublet mixer concept”. Thus, two mixing air holes are provided per fuel nozzle. According to the state of the art, the mixing air holes are embodied so as to be provided with a substantially tubular air conduit that extends relatively far into the interior space of the combustion chamber. The problem that occurs here is that the air conduits of the mixing air holes are relatively long and, as mentioned, project into the interior space of the combustion chamber and thus into the flame zone. Here, the air conduits can only be cooled to a very limited extent, so that they burn off during operation. But such a burnup leads to a significant change in the temperature distribution at the combustion chamber exit. This also leads to an increase in undesired NOX emissions. Thus, the combustion chambers that have so far been provided in connection with the “counter swirl doublet mixer concept” can be used only to a limited extent.